Simplified model predictive control of a three‐phase T‐type NPC inverter

Abstract

This study presents a simplified model predictive control (SMPC) strategy for three-phase T-type neutral-pointclamped (NPC) inverters to reduce the computational effort while achieving the current control, capacitor voltage equalisation and common-mode voltage (CMV) minimisation targets. The approach involves three stages. In the first stage, the number of switching states is reduced from 27 to 19 for reducing the peak CMV. In the second stage, a graphical approach is proposed to identify candidate control set (CCS) based on the present switching state, which helps in reducing the number of computations further. The number of elements in CCS may be 7, 10, 13 or 19. A look-up table with present applied state and its corresponding CCS is formed based on this graphical approach for all the 19 switching states. The third stage involves modifications to the MPC algorithm. Two versions of SMPC schemes (SMPC-I and SMPC-II) are proposed. SMPC-I can restrict the CMV to onesixth of DC input voltage. SMPC-II can achieve near zero CMV. The performance of the SMPC strategy is analysed with parameter uncertainty. Computational effort of SMPC schemes is compared with other MPC methods. The feasibility of SMPC algorithm is verified experimentally on T-type NPC inverter prototype.

Model predictive flexible power control for grid‐connected inverter under unbalanced network

“…As shown in Fig. 1, the three‐level inverter for grid‐connected system adopts the T‐type inverter on account of the less conduction loss and equal loss distribution among power switches [1, 2]. e abc and i abc refer to the grid voltage and the grid current in abc coordinates, respectively; both C 1 and C 2 are the dc‐link capacitors; L and R are the inductance of the output filter and its equivalent resistance, respectively.…”

“…Grid‐connected inverters as one group of power‐electronic interfaces, transferring electric energy from the primary sources to the power grids, are the critical devices [1–3]. The steady performances and dynamic responses of these inverters have a significant influence on their power qualities [4, 5].…”

An improved hysteresis current control scheme during grid voltage zero‐crossing for grid‐connected three‐level inverters

“…For the three‐level NPC inverters, the predictive current control is also a commonly used non‐linear control method due to its fast dynamic response. In [11], a simplified predictive control strategy for current control of the three‐level T‐type NPC inverter is presented. Moreover, aiming at improving the quality of output current, the multi‐step predictive control is proposed for the NPC grid‐connected inverter [12].…”

A Low-Complexity Modulated Model Predictive Current Control Scheme for PMSM based Starter Generator Control System in More Electric Aircraft

“…To make sure that satisfactory power quality at low switching frequencies is maintained as well as consideration of economic benefits, using a conventional silicon (Si) based multilevel converter is a good choice. This paper adopts a three-level neutral point clamped (NPC) converter in an ESG system, due to its lower switching losses and superior power quality compared to a two-level VSC [9]. The structure diagram of ESG is shown in Fig.1.…”